Nanomaterials offer advantages as new fuels and energetic materials because of increased surface areas, enhancement of chemical reactivity that often accompanies a reduction in particle size, and the ability to form composites. Applications include new energy storage devices and power sources. In this work, we report the synthesis of single-walled carbon nanotubes decorated with mono-, di-, and trinitrobenzenes via diazonium chemistry as a means of increasing their energy density. Differential scanning calorimetry confirms thermally initiated energy release from such systems, with no release from control materials. Analysis of calorimetric data shows a statistically lower value of activation energy at low conversion, providing evidence for nanotube-guided chain reactions. Although covalent functionalization introduces defects that tend to scatter electrons and phonons, reducing electrical and thermal conductivity, we show that thermopower waves are still able to rapidly propagate along such decorated nanotubes and produce electrical power. The results offer new ways of storing chemical energy within carbon nanotubes and new conduits for thermopower wave generators.